CSS is your bridge to low cost high quality FRP composite products

Composite Bladder Inflation Molding (BIM) Support

"Process complex hollow composite structures with confidence"

CSS has more than 35 years of experience supporting the design and manufacture of complex hollow FRP composite structures produced with Bladder Inflation Molding (BIM).

CSS helps Clients design and manufacture bladder molded prototypes and production parts from prepreg layups or resin infused preforms. Our BIM services include custom bladder design, BIM air fitting and tooling design, and BIM tailored product design and process development support.

CSS does not manufacture or sell bladders but we do support in-house bladder fabrication efforts or we can recommend bladder solutions for most applications.

Bladder Molding production implementation is supported through CSS' Composite Production Support services or, in the case of medium to high production volumes applications, CSS' Overseas Sourcing Services.

Bladder Inflation Molding Advantages

Prepreg Versus Resin Infused Preforms

BIM parts may be fabricated from hot melt prepreg preforms or dry fiber preforms infused with resin during the bladder molding process. The bladder's role and bladder inflation pressure differ depending on the preform type.

In the case of prepreg bladders, the bladder's role is to consolidate the prepreg layers and maintain the consolidated part shape until the resin matrix cures. Higher internal bladder pressures are typically employed to generate resin flow, drive entrapped air out of the layup, and consolidate the fiber reinforced prepreg layers against the tool surface.

Prepreg Bladder Inflation Molding


A resin infusion bladder, on the other hand, is typically inflated with less pressure to avoid collapsing the dry fiber preform and shutting off essential resin flow channels. The resin infusion bladder's role is that of a soft tool surface during impregnation and to maintain wetted preform shape as the resin gels/cures.

Resin Infusion Bladder Inflation Molding


Bladder material selection is driven by part geometry, processing temperature, reusability requirements, and cost. Common bladder materials include latex rubber, polyamides (nylon), silicone rubber, and polyetheretherketone (PEEK).

Bladder Inflation Molding Case Studies


Resin Infused Composite Spool Composite Bent Paddle Shaft Composite Stroller Frame Member